The volcano, about 100 miles from Anchorage, is throwing ash as high as 60,000 feet into the air. Air travel has been disrupted and health risks are up in some lightly populated areas.

DENVER AND SEATTLE — The eruption of a 10,200-foot Alaska volcano spewed ash up to 60,000 feet in the air, snarling air travel Monday and stranding small groups of people in remote, sparsely populated parts of the vast state.

The eruption of Mt. Redoubt, about 100 miles southwest of Anchorage, had a limited effect on the state's largest city and its suburbs. Winds blew the lower layer of ash into the Susitna Valley, where a mild coating of debris was reported in some rural areas.

Residents who had been bracing for the eruption for weeks were relieved that its impact was not more severe.

"It's been looming in the background here for a month and a half or so," said Capt. Tim Morgan of the Talkeetna Fire Department. "Finally it's here, and it's another day at the office."

The volcano erupted six times starting at 10:38 p.m. Sunday Alaska Daylight Time. The last reported eruption was at 7:41 p.m Monday.

Geologists said that eruptions could continue for weeks or months and that the largest impact would probably be on air travel.

Mt. Redoubt has erupted several times before, most notably for five months in late 1989 through 1990, when its ash stopped the engines of a KLM jet in mid-flight. The plane dropped two miles before its crew could reactivate the engines.

Aware of this history, Alaska Airlines canceled 19 flights Monday morning and continued to cancel flights north of Anchorage later in the day. Elmendorf Air Force Base near Anchorage sheltered 60 planes and functioned with a skeleton crew.

Chris Waythomas, a geologist at the Alaska Volcano Observatory, said Redoubt is one of a number of active volcanoes in the central and western part of the state that can wreak havoc on air travel. Last year, an Aleutian Islands volcano spread enough ash to shut down flights for a full day.

The jagged particles that constitute ash from volcanoes such as Mt. Redoubt do more than shred machinery. They can tear into eyes and skin and cause breathing problems.

In much of the affected region, residents awoke to a typical Alaskan March morning -- gray skies and pure white snow on the ground. They had to look carefully to see the fallout from the eruption.

"You can see it the air, like a distant forest fire," said Reinhard Grenz, owner of the Denali Outpost in Trapper Creek, about 175 miles from Redoubt. "There's a dusting on our deck, a trace."

Elsewhere the effects were more noticeable. In the town of Skwentna, the ash covered trees and blackened the snow. A sulfurous smell lingered in the crisp spring air. Families huddled indoors, unable to use their usual form of transportation -- snowmobiles -- and ran their generators intermittently to try to preserve the motors.

"It's covered everything up," said Katie Child, 18, as she huddled with her family inside the Skwentna Roadhouse, playing cards and watching television.

It wasn't just large commercial flights that were grounded. Rural Alaskans depend on flights between hamlets, as do tourists. At Talkeetna Air Taxi, workers stayed inside their offices. Planes were covered and computers bagged to protect against the ash, and workers were worrying about two groups they were supposed to pick up Monday morning that are now stranded.

Sandra Loomis, the company's manager, said both groups consist of "savvy, experienced backcountry travelers." One pair of climbers from Colorado is in the southern peaks of the Alaska Range, she said, and a party of four is at a hut on the side of Mt. McKinley.

Loomis said the climbers are only a couple of days' walk from Skwentna, and the group on Mt. McKinley has already reported having adequate supplies to last longer. "I'm just glad it's happening now and not when we're really busy," Loomis said. In the summer, there could be hundreds of people in the bush counting on flights out.

A normally hardy bunch, Alaskans in the affected areas said they are already looking forward to the end of the eruption.

"We wonder how long this thing is going to burp up these ashes," said Kathleen Huston, owner of a bed and breakfast in the town of Willow. "We want this thing to get its indigestion over with so we can go on vacation in a few days. It cancels all the airplanes -- and we've got plans."